The Java/Clojure QC of SurveyMan has a RandomRespondent built in. This RandomRespondent class generates answers to the surveys on the basis of some policy. The policies currently available are uniform random, first option, last option, and Gaussian. I've been thinking about some other adversary models I could add to the mix :

Christmas Tree : This is a variant of the uniform random respondent, where the respondent zigzags down the survey in the form of a "Christmas Tree."

Memory Bot : This is more like an augmentation to one of the existing policies, where the questions and answers are cached, and for each question, the bot checks whether it has answered something like it before. We know that sometimes researchers repeat questions, or have similarly worded questions with the same answers (e.g. year of birth). The goal of this bot would be to identify similarly worded questions and try to give consistent answers.

IR Bot : Alternately, we could search through Google for answers and use those answers as solutions.

It's fairly trivial to write some Javascript to answer our kind of surveys. Since we now have automated browser testing set up, we should also be able to test collusion in the context of the full pipeline. W00t!